JP5170329B2 - Development unit - Google Patents

Description

  The present invention relates to a developing unit that supplies developer to an electrostatic latent image formed on a photoreceptor.

  2. Description of the Related Art Conventionally, as a developing unit, a developing unit is known that includes a developing roller that carries a developer, a supply roller that supplies the developer to the developing roller, and an auger that conveys the developer in the axial direction of the supply roller (patent) Reference 1). Specifically, in this technique, two augers are arranged above and below the supply roller (specifically, one auger is provided near the supply roller and the other auger is arranged above the one auger). Thus, the toner in the developing chamber containing the supply roller and the like is agitated.

JP-A-9-319199

  However, in the prior art, since only one auger is arranged in the vicinity of the supply roller, the developer in a place where the auger around the supply roller is not arranged stays on the spot, and the developer is circulated well. There was a risk that it would be impossible. Further, for example, when the developer is transported in the axial direction by only one auger, the density distribution of the developer is uneven depending on the shape of the auger, and this causes unevenness in the amount of developer supplied to the developing roller by the supply roller. The problem occurs. When such a problem occurs, unevenness in the amount of the developer carried on the developing roller may occur, and there is a possibility that good printing cannot be performed.

  Accordingly, the present invention provides a developing unit capable of suppressing the stagnation of the developer around the supply roller (supply member) and suppressing unevenness in the amount of the developer on the developing roller (developer carrier). For the purpose.

  In order to solve the above-described problems, a developing unit according to the present invention includes a rotatable developer carrier that carries a developer, a rotatable supply member that supplies the developer to the developer carrier, and the supply member. A developing unit that is disposed above and includes a regulating member that slidably contacts the developer carrying member and regulates the thickness of the developer carried on the developer carrying member, and is disposed adjacent to the developing unit. A developer accommodating portion that accommodates the developer, and a plurality of conveying members that convey the developer in an axial direction of the supply member, wherein one of the plurality of conveying members includes the first conveying member The second transport member, which is disposed above the member and adjacent to the regulating member, is different from the first transport member in the circumferential direction of the supply member with respect to the first transport member. Arranged side by side, the developing unit includes the first conveying member and the By partitioning between the two transport members with a partition wall, a first storage chamber for storing the first transport member and a second storage chamber for storing the second transport member are formed, and a wall of the developing unit is formed. A supply port for a second storage chamber for supplying the developer from the developer storage section to the second storage chamber, and the development from the downstream side in the transport direction of the first transport member of the first storage chamber. A return port for the first storage chamber for returning the developer to the developer storage portion is formed, and the development portion is configured to be connected to the first storage chamber when the developer carrier, the supply member, and the transport member are driven. The position of the upper surface of the developer is configured to be lower than the position of the upper surface of the developer in the second storage chamber.

  According to the present invention, since the plurality of conveying members are arranged side by side in the circumferential direction of the supply member, the retention of the developer around the supply member can be suppressed. Further, for example, when the developer is sent to one axial direction by one conveying member, the density distribution of the developer is uneven depending on the shape of the conveying member, and thereby the amount of developer supplied to the developer carrier by the supply member is increased. Although the problem of unevenness may occur, the amount of developer supplied to the developer carrier by the supply member by the second conveyance member arranged side by side in the circumferential direction of the supply member with respect to the first conveyance member Unevenness can be reduced. Therefore, unevenness in the amount of the developer carried on the supply member and the developer carrying member can be suppressed.

  According to the present invention, it is possible to suppress the stagnation of the developer around the supply member, and to suppress unevenness in the amount of the developer carried on the developer carrying member.

1 is a cross-sectional view illustrating a color printer including a developing unit according to an embodiment of the present invention. It is an expanded sectional view which shows a developing device. It is XX sectional drawing of FIG. It is a disassembled perspective view which decomposes | disassembles and shows a developing unit. It is the rear view which looked at the developing device from back. FIG. 4 is a cross-sectional view (a) showing a developing unit and a side view (b) showing a gear mechanism. FIG. 4 is a cross-sectional view (a) of the developer cartridge 7 cut in the axial direction of the agitator and a cross-sectional view (b) cut in a direction perpendicular to the axial direction. It is sectional drawing (a) which shows the rotation direction of each agitator, and the side view (b) which shows the engagement state of the gear of each agitator. It is sectional drawing which shows the developing unit which provided two supply ports and two return ports. FIG. 10 is a cross-sectional view of the developing device of FIG. 9 cut in the axial direction of the auger. FIG. 10 is an exploded perspective view showing the developing unit of FIG. 9 in an exploded manner.

Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
In the following description, the direction will be described with reference to the user when using the color printer. That is, in FIG. 1, the right side toward the paper surface is “front side (front side)”, the left side toward the paper surface is “rear side (back side)”, the back side toward the paper surface is “right side”, and it faces the paper surface. The front side is the “left side”. In addition, the vertical direction toward the page is defined as the “vertical direction”.

<Overall configuration of color printer>
As shown in FIG. 1, the color printer 1 includes an apparatus main body 2, a feeder unit 3, an image forming unit 4, and the like.

  The apparatus main body 2 is formed in a hollow case shape, and an opening 2A is formed on the front wall thereof, and a front cover 21 that opens and closes the opening 2A is swingably provided. A paper discharge tray 22 on which printed paper is placed is provided on the upper part of the apparatus main body 2.

  The feeder unit 3 includes a paper feed tray 31 and a paper supply mechanism 32. In the feeder unit 3, the sheets in the sheet feeding tray 31 are separated one by one by the sheet supply mechanism 32 and conveyed to the image forming unit 4.

  The image forming unit 4 includes a scanner unit 41, four (plural) process cartridges 42, a belt unit 43, a fixing device 44, and the like.

  The scanner unit 41 has a known structure mainly including a laser light emitting unit (not shown), a polygon mirror, a lens, a reflecting mirror (not shown), and the like. In the scanner unit 41, the laser beam is irradiated on the surface of the photosensitive drum 51 of the process cartridge 42 by high-speed scanning through a path indicated by a two-dot chain line in the drawing.

  Each process cartridge 42 is supported by a drawer 45 that can be pulled forward from the opening 2 </ b> A of the apparatus main body 2, and is attachable to and detachable from the drawer 45. Each process cartridge 42 mainly includes a drum cartridge 5, a developing device 6 that can be attached to and detached from the drum cartridge 5, and a developer cartridge 7 that can be attached to and detached from the developing device 6.

  The drum cartridge 5 includes a photosensitive drum 51, a charger 52, and the like.

  As shown in FIG. 2, the developing device 6 includes a developing roller 61 as an example of a rotatable developer carrier, a layer thickness regulating blade 62 as an example of a regulating member, and an example of a rotatable supply member. A supply roller 63 is mainly provided. As shown in FIG. 1, the developer cartridge 7 has a structure in which a toner as an example of a developer is accommodated, and this toner can be sent to a developing device 6 adjacent below. The developing device 6 and the developer cartridge 7 will be described in detail later.

  In the process cartridge 42 configured as described above, the toner sent into the developing device 6 from the developer cartridge 7 is supplied to the developing roller 61 by the supply roller 63. At this time, the supply roller 63, the developing roller 61, Is positively triboelectrically charged. The toner supplied onto the developing roller 61 is regulated in thickness by a layer thickness regulating blade 62 that is in sliding contact with the developing roller 61, and is carried on the developing roller 61 as a thin layer having a constant thickness.

  On the other hand, in the drum cartridge 5, the surface of the photosensitive drum 51 is uniformly positively charged by the charger 52 and then exposed by high-speed scanning of the laser beam from the scanner unit 41. Thereby, the potential of the exposed part is lowered, and an electrostatic latent image based on the image data is formed. Next, the toner on the developing roller 61 is supplied to the electrostatic latent image on the photosensitive drum 51, so that a toner image is formed on the surface of the photosensitive drum 51.

  The belt unit 43 mainly includes a conveyance belt 43A that conveys paper, and a transfer roller 43B that is disposed in the conveyance belt 43A so as to face each photosensitive drum 51 with the conveyance belt 43A interposed therebetween.

  In the belt unit 43, the toner image on the photosensitive drum 51 is transferred onto the sheet P when the sheet conveyed by the conveying belt 43A passes between the photosensitive drum 51 and the transfer roller 43B.

  The fixing device 44 includes a heating roller 44A and a pressure roller 44B. In the fixing device 44, the toner transferred onto the sheet is thermally fixed while the sheet passes between the heating roller 44A and the pressure roller 44B. The heat-fixed paper is discharged onto the paper discharge tray 22 by a paper discharge roller 46 disposed on the downstream side of the fixing device 44.

<Details of Development Device and Developer Cartridge Structure>
Next, the structure of the developing device 6 and the developer cartridge 7 will be described in detail. In the present embodiment, the developing unit DU (see FIGS. 1 and 4) is configured by combining the developing device 6 and the developer cartridge 7.

  As shown in FIG. 2, the developing device 6 includes the developing roller 61, the layer thickness regulating blade 62, and the supply roller 63 described above, and accommodates two augers 64 as an example of a plurality of conveying members and these components. A developing case 65 is provided as an example of the developing unit.

  The layer thickness regulating blade 62 is disposed above the supply roller 63 (specifically, above the contact position between the supply roller 63 and the developing roller 61).

  Each auger 64 is a member that conveys toner in the axial direction of the supply roller 63, and is arranged side by side in the circumferential direction of the supply roller 63 in the vicinity of the peripheral surface of the supply roller 63. Specifically, of the two, the first auger 641 as an example of the first transport member is disposed above the supply roller 63 and adjacent to the layer thickness regulating blade 62, and The second auger 642 as an example is disposed above the supply roller 63 and at a position adjacent to the first auger 641.

  As shown in FIG. 3, each auger 64 includes a rotation shaft 64A and a spiral blade 64B provided so as to be wound around the rotation shaft 64A in a spiral shape. The first auger 641 rotates in one direction to convey the toner from left to right, and the second auger 642 rotates in the direction opposite to the first auger 641 to move the toner from right to left. Conveying.

  As shown in FIG. 2, the first auger 641 and the second auger 642 are partitioned by a partition wall 65 </ b> A, whereby the first storage chamber R <b> 1 that stores the first auger 641 in the developing case 65. And a second storage chamber R2 for storing the second auger 642 is formed. In the developing device 6, when the developing roller 61, the supply roller 63, and each auger 64 are driven (when printing is controlled), the position of the toner upper surface TF1 of the first storage chamber R1 is set to the toner upper surface of the second storage chamber R2. It is configured to be lower than the position of TF2.

  Specifically, a supply port 65C for supplying toner from the developer cartridge 7 to the second storage chamber R2 is formed on the right side of the upper wall 65B of the development case 65 (upstream in the conveyance direction of the second auger 642). ing. As shown in FIGS. 2 and 3, on the left side of the partition wall 65A (on the downstream side in the transport direction of the second auger 642), a communication port 65D for sending toner from the second storage chamber R2 to the first storage chamber R1. Is formed.

  Further, as shown in FIG. 3 and FIG. 4, it is arranged on the right end side (downstream in the transport direction of the first auger 641) of the first storage chamber R <b> 1 and is formed so as to face the right end portion of the first auger 641. A return port 65F for returning the toner from the first storage chamber R1 to the developer cartridge 7 is formed in the lower portion of the cylindrical wall 65E. Note that FIG. 4 (also in FIG. 11 described later) shows the developer cartridge 7 looking up from below and the developing device 6 looking down from above for convenience.

  As shown in FIG. 5, the communication port 65D is disposed above the return port 65F. As a result, as shown in FIG. 2, the position of the toner upper surface TF1 of the first storage chamber R1 is lower than the position of the toner upper surface TF2 of the second storage chamber R2. That is, the toner supplied from the supply port 65C to the second storage chamber R2 accumulates in the second storage chamber R2 until it reaches the communication port 65D. When the toner that reaches the communication port 65D is supplied to the first storage chamber R1, the toner is transported to the return port 65F by the first auger 641 and exits from the first storage chamber R1 at any time. The toner upper surface TF1 in the first storage chamber R1 can be made lower than the toner upper surface TF2 of the second storage chamber R2.

  Further, the transport capability of the first auger 641 is configured to be higher than the transport capability of the second auger 642. Here, the conveyance capability means a toner conveyance amount per unit time. As a result, the amount of toner discharged from the first storage chamber R1 is larger than the amount of toner sent from the second storage chamber R2 to the first storage chamber R1, and thus the first storage chamber is more reliably provided. The toner upper surface TF1 in R1 can be made lower than the toner upper surface TF2 of the second storage chamber R2.

  In addition, as a method of giving a difference in conveyance capability, there are a method of making a difference in the rotation speed of each auger 64, a method of changing the wing size and angle of each auger 64, and the like. In this embodiment, as shown below, the rotational speed of each auger 64 is made different by the reduction gear.

  Specifically, as shown in FIGS. 6A and 6B, a two-stage gear G1 functioning as a reduction gear is provided at the end of the first auger 641 so as to be integrally rotatable. A gear G2 (substantially the same diameter as the large-diameter gear portion G12 of the two-stage gear G1) that meshes with the small-diameter gear portion G11 of G1 is provided at the end of the second auger 642 so as to be integrally rotatable. Thereby, the rotational speed of the first auger 641 is configured to be faster than the rotational speed of the second auger 642.

  Note that the large-diameter gear portion G12 of the two-stage gear G1 can rotate integrally with the rotation shaft of the developing roller 61 and the gear G3 provided in the developer cartridge 7 so as to rotate integrally with a rotation shaft of an agitator A1 described later. Is engaged with a gear G4 provided on the rotary shaft of the supply roller 63 and a gear G5 provided so as to be integrally rotatable with the rotation shaft of the supply roller 63. And each gear G1-G5 rotates because driving force is transmitted from the apparatus main body 2 to either of these gears G1-G5.

  As shown in FIGS. 7A and 7B, the developer cartridge 7 includes a toner case 7A as an example of a developer container, and four agitators A1 to A4 for stirring and transporting the toner. It is configured.

  The toner case 7 </ b> A includes a substantially hollow cylindrical toner storage chamber 71 that can store toner, and a return flow path 72 for returning the toner from the developing device 6 to the toner storage chamber 71. A supply port 71A formed at a position and size corresponding to the supply port 65C of the developing case 65 described above is provided below the toner storage chamber 71 (see also FIG. 4).

  The return channel 72 is formed so as to extend downward from the left and right outer ends of the toner storage chamber 71 and then extend inward in the left and right directions. A return port 72A formed at a position and size corresponding to the return port 65F of the developing case 65 is disposed (see also FIG. 4).

  The agitator A1 is an agitator for supplying toner from the toner storage chamber 71 to the developing device 6, and is supported by the rotation shaft portion A11 rotatably supported by the left and right walls of the toner storage chamber 71 and the rotation shaft portion A11. A plurality of films A12 and A13. Of the plurality of films A12 and A13, the transport film A12 disposed to face the supply port 71A is formed in a rectangular shape, and the other alignment films A13 can draw toner toward the supply port 71A. It is formed into a shape. Specifically, the advancing film A13 has a rotational direction such that the end on the rear side in the rotational direction is positioned on the supply port 71A side with respect to the end on the front side in the rotational direction of the agitator A1 (the end in sliding contact with the wall surface). It is in sliding contact with the wall surface of the toner storage chamber 71 in an inclined state.

  The agitators A2, A3, and A4 are arranged in three chambers R3, R4, and R5 that are formed adjacent to each other in the return flow path 72, and are configured to lift and convey the toner to the upper chambers. ing. Specifically, the agitators A2, A3, and A4 are mainly supported by the rotation shaft portions A21, A31, and A41 and the rotation shaft portions A21, A31, and A41, and two transport films A22 for feeding the toner upward. , A32, A42. In addition, the rotation shaft portion A41 of the lowermost agitator A4 has a shape capable of attracting toner from the return port 72A to the transport film A42 (the end on the rear side in the rotational direction is transported more than the end on the front side in the rotational direction). A moving film A43 having a shape (positioned on the film A42 side) is provided.

  As shown in FIG. 8B, gears G21 to G24 are provided at one end of each agitator A1 to A4 so as to be integrally rotatable, and each gear G21 to G24 is connected to a gear of an adjacent agitator. Each biting. Thereby, as shown to Fig.8 (a), the rotation directions of adjacent agitators (for example, agitator A3, A4) are mutually reverse directions.

  Then, by rotating the rotation directions of the adjacent agitators in this way, for example, the agitator in the upper chamber R4 with respect to the supply port R51 for supplying toner from the lower chamber R5 to the upper chamber R4. Rotate so that A3 moves away. As a result, it is possible to prevent the toner from flowing backward by pushing the toner into the supply port R51 by the agitator A3 in the upper chamber R4.

  7A, the toner that has entered the return flow path 72 from the return port 72A is returned to the toner storage chamber 71 through the return flow path 72 by the agitators A2 to A4. It is. Further, the toner in the toner storage chamber 71 is moved toward the supply port 71A by the advancing film A13 of the agitator A1, and then sent to the developing device 6 from the supply port 71A through the transport film A12. It should be noted that the conveyance capability of the agitators A2 to A4 for returning the toner from the return port 72A to the toner storage chamber 71 is higher than the conveyance capability of the auger 64.

According to the above, the following effects can be obtained in the present embodiment.
Since the plurality of augers 64 are arranged side by side in the circumferential direction of the supply roller 63, toner retention around the supply roller 63 can be suppressed. Further, when the first auger 641 sends the toner in one axial direction, the shape of the auger 64 causes unevenness in the density distribution of the toner. Although a problem may occur, unevenness in the amount of toner supplied from the supply roller 63 to the developing roller 61 by another second auger 642 arranged along the circumferential direction of the supply roller 63 with respect to the first auger 641. Can be reduced. Therefore, unevenness in the amount of toner carried on the supply roller 63 and the developing roller 61 can be suppressed.

  When the developing roller 61 is driven, the position of the toner upper surface TF1 of the first storage chamber R1 is lower than the position of the toner upper surface TF2 of the second storage chamber R2, so that the contact between the developing roller 61 and the layer thickness regulating blade 62 is achieved. The pressure of the toner applied to the position is reduced, and toner leakage from the contact position (a toner amount more than necessary passes through the contact position) can be suppressed.

  Since the communication port 65D is disposed above the return port 65F, the toner upper surface TF1 in the first storage chamber R1 can be surely made lower than the toner upper surface TF2 of the second storage chamber R2.

  Since the conveyance capability of the first auger 641 is configured to be higher than the conveyance capability of the second auger 642, the toner upper surface TF1 in the first storage chamber R1 can be more reliably attached to the toner upper surface of the second storage chamber R2. It can be lower than TF2.

In addition, this invention is not limited to the said embodiment, It can utilize with various forms so that it may illustrate below.
In the above-described embodiment, the route in which the toner supplied from the developer cartridge 7 returns to the developer cartridge 7 through the developing device 6 is a single route (supply port 65C → second storage chamber R2 → communication port 65D). → First storage chamber R1 → return port 65F), but the present invention is not limited to this. For example, as shown in FIGS. 9 to 10, it may be configured by two routes. In addition, in the form of FIGS. 9-11, about the component substantially the same as the said embodiment, the same code | symbol is attached | subjected and the description shall be abbreviate | omitted.

  Specifically, on the left side of the upper wall 65B of the developing case 65 (upstream in the conveyance direction of each auger 64), a first supply port 65G for supplying toner from the toner case 7A to the first storage chamber R1, A second supply port 65H for supplying toner from the toner case 7A to the second storage chamber R2 is formed. The toner case 7A also has a first supply port 71G and a second supply port 71H corresponding to the first supply port 65G and the second supply port 65H.

  9 to 11, the structure itself of each auger 64 is the same as that of the above embodiment, but as shown in FIG. 10, the left and right directions of the first auger 641 (the spiral direction of the spiral blade 64B). However, since each of the augers 64 is transported in the direction from the left to the right, the direction of the auger 64 is directed from the left to the right.

  As shown in FIGS. 10 and 11, the right wall 65J of the developing case 65 (the wall facing the downstream end of each auger 64 in the transport direction) is connected from the first storage chamber R1 to the toner case 7A. A first return port 65K for returning the toner and a second return port 65L for returning the toner from the second storage chamber R2 to the toner case 7A are formed. The toner case 7A also has a first return port 71K and a second return port 71L corresponding to the first return port 65K and the second return port 65L.

  With this configuration, the toner is separately supplied from the toner case 7A to the storage chambers R1 and R2 via the two supply ports 65G and 65H, and the return ports are separately supplied from the storage chambers R1 and R2. The toner is returned to the toner case 7A through 65K and 65L.

  The opening area of the second supply port 65H is formed larger than that of the first supply port 65G. As a result, the speed at which the toner is deposited in the second storage chamber R2 becomes faster than the speed at which the toner is deposited in the first storage chamber R1, so that the upper surface of the toner in the first storage chamber R1 as shown in FIG. The position of TF1 can be surely made lower than the position of the toner upper surface TF2 of the second storage chamber R2.

  As shown in FIG. 10, the opening area of the second return port 65L is smaller than that of the first return port 65K. Accordingly, since the speed at which the toner is discharged from the second storage chamber R2 can be made slower than the speed at which the toner is discharged from the first storage chamber R1, the position of the toner upper surface TF1 of the first storage chamber R1 is set. In addition, it is possible to make the level lower than the position of the toner upper surface TF2 of the second storage chamber R2.

  9 to 11, the opening areas of the two supply ports 65G and 65H are configured to be different and the opening areas of the two return ports 65K and 65L are also different. The present invention is not limited, and only the opening area of one of the two supply ports and the two return ports may be varied. That is, for example, the opening areas of the two supply ports 65G and 65H may be different, and the opening areas of the two return ports may be the same size.

  9 to 11, the opening areas of the two supply ports may be the same size, and the opening areas of the two return ports may be the same size. Even in this case, the toner upper surface TF <b> 1 of the first storage chamber R <b> 1 is configured by configuring the first auger 641 to have a higher conveying capacity than the second auger 642, as in the above embodiment. Can be made lower than the position of the toner upper surface TF2 of the second storage chamber R2.

  In the above-described embodiment, both the configuration in which the communication port 65D is disposed above the return port 65F and the configuration in which the conveyance capability of the first auger 641 is higher than that of the second auger 642 are adopted, but the present invention is limited to this. Instead, only one of them may be adopted.

  In the above-described embodiment, each of the developing unit and the developer storage unit is configured with two components (the development case 65 and the toner case 7A). However, the present invention is not limited to this, and the development unit and the developer storage unit are configured as one component. You may comprise integrally. That is, the developing unit may be composed of one component instead of two components.

  In the embodiment, two augers 64 are provided. However, the present invention is not limited to this, and may be three or more as long as there are a plurality of augers.

  In the above-described embodiment, the layer thickness regulating blade 62 configured by attaching rubber to the tip of the metal plate is employed as the regulating member. However, for example, a blade configured only by a metal plate without rubber may be employed. .

  In the above embodiment, the present invention is applied to the color printer 1. However, the present invention is not limited to this, and the present invention may be applied to other image forming apparatuses such as monochrome printers, copiers, and multifunction machines. Good.

  In the above-described embodiment, the agitators A2 to A4 are used as the return conveyance members for returning the toner from the developing device 6 to the toner storage chamber 71. However, the present invention is not limited thereto, and may be an auger, for example. .

6 Developing Device 7 Developer Cartridge 7A Toner Case 61 Developing Roller 62 Layer Thickness Restricting Blade 63 Supply Roller 64 Auger 65 Developing Case 65A Partition 65C Supply Port 65D Communication Port 65F Return Port 641 First Auger 642 Second Auger DU Development Unit R1 First 1 storage room R2 2nd storage room

Claims (5)

A rotatable developer carrier that carries the developer, a rotatable supply member that supplies the developer to the developer carrier, and a sliding member that is disposed above the supply member and is in sliding contact with the developer carrier. A developing member having a regulating member that regulates the thickness of the developer carried on the developer carrying body,
A developer accommodating portion disposed adjacent to the developing portion and accommodating a developer;
A plurality of conveying members that convey the developer in the axial direction of the supply member,
One first conveying member of the plurality of conveying members is disposed above the supply member and at a position adjacent to the regulating member, and is a second conveying member different from the first conveying member. Are arranged side by side in the circumferential direction of the supply member with respect to the first transport member,
In the developing section,
By partitioning the first transport member and the second transport member with a partition wall, a first storage chamber for storing the first transport member and a second storage chamber for storing the second transport member are formed. And
On the wall of the developing unit, a supply port for a second storage chamber for supplying the developer from the developer storage unit to the second storage chamber, and transport of the first transport member of the first storage chamber A return port for the first storage chamber for returning the developer from the downstream side to the developer storage portion is formed;
The developing unit is
The position of the upper surface of the developer in the first storage chamber is lower than the position of the upper surface of the developer in the second storage chamber when the developer carrier, the supply member, and the transport member are driven. A developing unit. On the wall of the developing unit,
A supply port for the first storage chamber for supplying the developer from the developer storage portion to the first storage chamber is formed;
The developing unit according to claim 1, wherein an opening area of the supply port for the second storage chamber is formed larger than that of the supply port for the first storage chamber. On the wall of the developing unit,
A return port for the second storage chamber for returning the developer to the developer storage portion from the downstream side in the transport direction of the second transport member of the second storage chamber;
The developing unit according to claim 1, wherein an opening area of the return port for the second storage chamber is smaller than that of the return port for the first storage chamber. A communication port for sending developer from the second storage chamber to the first storage chamber is formed on the downstream side of the partition in the transport direction of the second transport member,
2. The developing unit according to claim 1, wherein the transporting capability of the first transporting member is configured to be higher than the transporting capability of the second transporting member. On the wall of the developing unit,
A supply port for a first storage chamber for supplying a developer from the developer storage portion to the first storage chamber;
A return port for the second storage chamber for returning the developer to the developer storage portion from the downstream side in the transport direction of the second transport member of the second storage chamber,
2. The developing unit according to claim 1, wherein the transporting capability of the first transporting member is configured to be higher than the transporting capability of the second transporting member.

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